Optical comparison hemoglobinometer with switch for use of selfcontained or external ower sources



Nov. l, 1949 H. F. LUNDBERG OPTICAL COMPARISON HEMOGLOBINOMETER WITH SWITCH FOR USE OF SELF-CONTAINED OR EXTERNAL POWER SOURCES Filed NOV` 24, 1945 2 Sheets-Sheet l ATTORNEY Nov. l, 1949 v H, F, LUNDBERG 2,486,956

OPTICAL COMPARISON HEMOGLOBINOMETER WITH swITcH FOR UsE OF SELF-CONTAINED OR EXTERNAL POWER SOURCES Filed Nov. 24, 1945 2 Sheets-Sheet 2 ATTURNEY Patented Nov. 1, 1949 OPTICAL COMPARISON HEMOGLOBINOM- ETER'WITH SWITCH FOR USE 0F SELF- CONTAINED 0R EXTERNAL POWER SOURCES Harry F. Lundberg, Buffalo, -N. Y.,4 assignor lto American Optical Company, Southbridge, Mass.,

a voluntary association of Massachusetts Application vNovember 24, 1945, Serial No' 630,610

This invention relates to hemoglobinome'ters, and :more particularly to vsuch an instrument which is compact and convenient for ruse :by a 'physician .inhis oiicehand which is also readily portable so that it` may be easily carried by the physician' in hismedicine 'kit'and used anywhere by yhim `for/rapidly and accurately examining the hemoglobinzcontent .of arlpatents blood. This application is animprovementover copending application Serial No. 440,476,`1ed April l25,1942 and issued March 12, 1946 as Patent No. 2,396,260.

In .the fhemoglobinometer'shown and described in said earlier led application .an electric bulb :is employed for illuminating the blood specimen and a standard comparison member `toube observed'xthrough at'sighting arrangement housed within a casing, and a pair of batteries of the conventional dry cellstype is enclosed therewith and serves as the sole means for supplying energy to the bulb. A diilculty resulting from such a construction yresides in the fact that repeated use of the device exhausts the batteries and this, consequently, necessitates frequent replacement thereof by lnew cells. Furthermore,` poor or -insuflicient illumination ofthe -bloodspeci-men and l comparison member when the rcells are weak might impair theaccuracy of operation of the .instrument. Since such an instrument is generally used by aphysician at` locations where a conventional-'external source of electric current or energy is available, it has been found-desirable to construct: and .arrange the instrument of the present invention f with4 suitable lmeans for selectively employing such external current or Ibatteries at places where outside current is not conveniently A available.

Accordingly, an-object of vthe invention is to provide such an instrument having means wherebyelectrical energy'from an external source'may be employed when convenient and means whereby a battery-or batteries may be employed when external 'source is not readily available. Such an arrangement materially extends the life of the batteries of thedevice, adding greatly to the `convenience and efficiency of the instrument.

An additional object ofv ther invention is toprovide a newA and improved hemoglobinometer which is compactand easy to handle'and adapted for use selectively with self-contained "dry `cells or an outside source o-i electrical energy.

:Another :object of the invention is to provide a device which williunction automatically upon its batteries when used alone, and which will .automatically render the 'batteries inoperative for supplying energy when the deviceu is pluggedin -for use withan externalsourceof current.

Another object of the vinvention is to provide a. device of the type set'forth which isstrong, durable, eiiicientand accurate its operation and at the same timeis Aof. a size, shape and weight which will :allow the instrument to be conveniently vhandled and vtransported with ease.

Other objects `and :advantages of the invention will becomeapparent from the following description taken in-:connection with the accompanying drawings. It will be apparent that .many changes may be madeinthe details of construction and arrangement of the'parts without departing from the .spirit -of vthe invention ras expressed by the accompanying claims. I do not therefore wish to be limited to theeXact-details of construction and arrangement of partsshown and described as the preferred form has been shown by way of illustration-only.

Referring to the drawings:

Fig. 1 is a side elevational View of. the instrument of the invention, the lower part thereof being shown in section by full lines while the upper part thereof is shown onlyin diagrammatical outline;

Fig. 2 is a transverse sectional view taken 'substantiallyon line 2-2 of Fig. 1 and looking in the direction of the arrows;

Fig. 3 is a fragmentary side elevational view showing certain parts in section andin one position of operation;

Fig. 4 is afragmentary sectional view taken substantially on vline 4-4 of Fig. 3 and looking in the direction of the arrows;

Fig. 5 is a fragmentary sectional view taken on line 5 5 of Fig. 3;

Fig. 6 isan isometric exploded View of the electrical .conductors employed in the invention; and

Fig. 7 is a fragmentary` sectional view of a modification .of the invention.

Referring more particularly to the drawings iwherein similar reference characters designate corresponding parts .throughout the several views, the device or instrument shown in Figs. 1-6 comprises 4a housing or casing generally indicated by the numeral 'l and formed of two separable sections 2 and 3 having intertting abutting edges 4 and 5, respectively, which may be detachably secured together by screws, resilient clips or the like (not shown). l

The sections 2 and 3 of the casing are preferably made of molded plastic or similar material but may be formed from any other desired material. The upper casing section 3 is provided with a sighting chamber 6 extending longitudinally of the casing section and has formed in an end wall of the section an eye piece Il. Intermediate the ends of the section 3 is located a bi-prlsm Ill for reflecting images of the blood on a specimen holder or carrier I2 and of a standard comparison member or wedge I4 to the eye piece 8. The standard member I4 is longitudinally adjustable in the compartment or guideway I6 for placing various portions of the member adjacent the carrier I2. Since the details of construction and operation of these parts of the device are clearly set forth in said earlier filed application and form no part of the present invention, they will not be discussed in detail herein.

The lower section 2 is provided with illuminating means I8 comprising an electric bulb 2S threaded into a socket 24, of electrically conductive material, and a semi-spheroidal reflector 22 frctionally engaging said socket. The bulb 20 is centrally located substantially midway of the length of the section 2 and in optical alignment with the specimen carrier I2, an adjacent portion of the standard member I4 and the reflecting biprism I for illuminating the blood specimen and a portion of the member I4 positioned adjacent thereto as clearly shown by Fig. l. is secured to the section 3 to enclose the operating parts within the section. A diffusing plate 23 is centrally carried by partition 25 overlies an aperture 26 in the partition so as to allow light from the illuminating means to reach the carrier I2 and member I4.

Positioned at opposite sides of the illuminating means I8 and longitudinally within the section 2 are electric batteries 21 and 28, preferably of a standard small dry cell type, and these are arranged to rest upon inwardly projecting integral lugs or ribs 3D formed upon the inner rounded wall of the casing 2 adjacent the opposite ends of each battery. An electrical conductor 32 is arranged centrally of the lower section 2 of the casing and extends through slots 33 formed in the ribs 36. Conductor 32 is adjustably secured in place by suitable means such as a screw 34 threaded into a metallic bushing 36 embedded in a portion of the molded plastic section 2. An outer free arm portion 38 of the conductor 32 is bent upwardly and inwardly to form a shoulder 4U and then bent slightly outwardly to provide a cam portion 42 for resiliently receiving and securely retaining the battery 27 in place in section 2 and for providing a firm electrical contact with an edge portion of a battery terminal as indicated at 44. The opposite end of the conductor 32 is bent upwardly and then horizontally to provide a supporting plate portion 46 which rests upon the integral lugs 48 arranged at opposite sides of the section 2. This supporting plate portion 46 is enlarged, as shown by Figs. 2 and 6, to accommodate a central aperture U for receiving the base portion of the socket 24 in spaced relation thereto. Upon the portion 46 is carried an insulating member 52 provided with an aperture for accommodating said socket and positioned thereon is a conductor 54 having an aperture 56 for receiving said socket. An arm 58 extends laterally theree A partition y CFI 4 from for engaging the opposite end wall of the battery 27.

The enlarged plate portion 46, insulating member 52 and conductor 54 are substantially of the same size and shape when viewed from above, and each is provided with recesses 66 located centrally in theside edge portions thereof to serve as centering means arranged to straddle integral lugs or ribs 62 projecting inwardly from the inner wall oi the section 2. It will be noted that opposite corner portions of the portion 46 have been removed or omitted to form bays 54 and corresponding opposite corner areas oi the insulating member 52 and the conductor 54 have been provided with apertures as indicated at 56 for receiving securing screws 68 threaded into position in the supporting lugs 48 of the molded section 2 to retain the parts 46, 52 and 54 securely in place upon the lugs 48. The bays 64 serve to space the plate portion 46 from the screws 68 and thus the portion 46 is electrically insulated from the conductor 54. The socket member 2li is secured to the conductor 54 and, as will be seen by Fig. 1, is maintained thereby in spaced relation to the member 46, an inner upwardly bent ring portion Ill of the conductor being crimped, soldered, crazed or otherwise secured to the socket as shown at 12.

The conductor -54 is provided with a second arm '.4 extending longitudinally from the opposite edge of the conductor from the iirst mentioned arm 53 and this arm T4 is bent upwardly near its outer end and formed with a portion 'I6 apertured to receive a terminal member 'I8 embedded in or otherwise secured to a molded terminal box or junction means 8D, which box or block is retained in place upon integral abutments BI at the end of the section 2 by screws B2 extending downwardly through the block and threaded into said abutments. A second terminal member 83 is provided in block 8l] in engagement with an end portion 84 of a resilient arm 86 of conductor 88 and this conductor is provided with an enlarged stiffened or flanged central portion which is apertured and forms a securing and supporting means therefor. The conductor 88 is also provided with an elongated arm 92 having a exible portion 94 adjacent the central portion and outwardly thereof is a portion Q6 stiilened by a central rib 98 to provide sufficient resiliency to respond to the manual actuation of a push button |00 positioned in the bottom central wall of the casing section 2. This resiliency firmly returns the button to its normal position when the pressure thereon is removed. A contact area H12 is formed in the free end of arm 52 and arranged to engage the center contact |04 of the bulb 20 when the push button is pressed. The push button IDI] is guided by the Walls of an aperture m6 and is prevented from moving outwardly beyond normal position by a skirt portion |08 engaging a recessed portion IIU of the section 2.

The plate portion 4E of the conductor 32, previously referred to, is provided with an upwardly and longitudinally bent nger II2 to contact an end wall of the battery 28. The center contact of the battery 28 at the opposite end thereof engages an upstanding arm II4 as indicated at II6, said arm having the general shape of the arm 38 when viewed :from the side, but is somewhat wider in its transverse direction to provide a central struck out arm II8 carrying a contact point IZB, said arm extending as a substantially rigid member from the horizontal base portion 5 :of a `conductor :1| 22. 'This conductor .|22 ,-is 'provided with downwardly;#centi lateral flanges .-l 24 to give ,rigidityfztotthe entire base portion .oiathe .conductorandto supprt1the1armx||8 in alproper positionA notwithstanding a the flexing off arm v| 4 carried i thereby.

. .The1 conductor fi 22. .s is zarranged f; toi Vfit over, a dianged insulating r member |26:: whichr4 Amember in .turnxstraddles a-.angedfconductor :I 28 :straddling l:conductorfffpspreviously .referred to;:. a second :insulating `member .1I-30: being positioned belowthe member :88. MAs will r-bef-seeniby" Fig. 5, these; .five members vare securely vheld .in anested relation ,by a rivet .|32 v"oinon.conductive 4material positioned v.in alignedwopenings |33 so that .said members .in han :assembled condition 'may l be inserted .into section 2 fandesecuredvtofbushings |34; embedded inisaid :casing fsection by fscrews |36 vextending f. .downwardly through V spaced aligned apertures 1:38 inv said nestedmembers` As Vbestshown by Figs. 1 and 6 the .spaced'apertures in the 4`plates-:88 :and .|;-28iare somewhat larger than :those of the .otherrinestedfmembers asfrlndicated at .fr|:38';so'that thefmembers 188 and |28 will be spacedsfrom andthus insulatedy from bushings .|34 Aand'screws |36 and .th-us .'fromthe conductor =|22. Iny order tov insure a good fpermanent electrical: connection -between conductors 'B8-'sand |28alateralanged portions |40 :thereof may fbe .extended downwardly'beyond the .ad-. jacent edges of the other: :nested members (see Fig. Vand,solderedbrazed .oraotherwise .suitably connected as indicated at |42.

The conductor|:28fhas a resilient arm |44 4extending from anend thereoizon whichtis carried a relatively: rigid. yflanged portion'd 46 that is bent upwardly rat .an `angle and provided atfthe :upper end thereof is a-horizontalA bearing surface'l48 adapted to ybefengaged byfan operatingwmember to -be presently described. The Acentral portion of this upwardly extending arm y|;l||'fis .apertured as at |50, .see Fig. 4, .to-.formi a ,resilientflnger |52 extending gupwardly and carrying :contact point |54 ladapted to make, `at-certain times', an electrical connection with contact point |son arm H8. The aperture :I 5t` is -rnade ofsuiiicient size to accommodate inspaced relation thereto the conductor :'66 Iextending therethrough.

The `iianged portion-|46. as stated; is resiliently supported by the.-y arm |44 so' thatiit xmayxbe pressed downwardly by anoperating member :|56 which, in the present instance, issformed'asran elongated vtubular member extending transversely of the terminal block and having its :opposite ends :retainedinfrecesses |58 .formed by portions :of the casing Zand yadjacent portions yoiuthe block 80 as indicated by. numerals "|59 and |60. 'From the foregoing description itwill .be seen'k that vthe operating member |56 may be moved from "the position showny in Fig. 1,-wherein this zmemberfis in araised position and the contact points 20. and |1541fare in contact,to itsdepressed position shown by Fig. 3 at which time the saidncontact points fare spaced from each other. .An electrical attachment or socket l|62 `having aconventional flexible cord |64 for-attachment .toan external source of electrical energyis provided', as-shown by Fig; 3, for insertion through the opening |65-in. thecasing section 2 into the recess |66 in the -terminal block 80 for effecting resilient frictionalelectrical con-,

nections with thefterminal members yi18 and 83. Opposite'cornerA portions-'fof this two-part 4separable socket |62 are vbevelled :or Aformed fas nam surfaces, vas .indicated .at 21.68, .,.to facilitate the' insertion of said lsocket .intoA therecess .1| 66,.;and zat? suchrtime, one offthese camsurfaces willrengage and :depress tubular member 1|56,:thus 'depressing the rarm` '|46I to interrupt 'the .ilow of. .current through the .contacts |20,` |54 Vand. thisy interruption willxtake place before acircuitisestablished between the' .conductors inthe'socket vandrthe terminals .18 :and :83.

. When. the physician desires to employ thefdevice .oft the invention :at locations removed fromv a convenient source of external power or energy, itisimerely necessary for him to depress the push button. |00 to establish a circuit through the proper conductorsitolight the .bulb 20 .byzenergy received `from the batteries 21 and .28. The circuit established'at such time `may be traced from the `push vbutton actuated arm 96 throughthe conductors '88and :|;28:to the contact point |54-'in engagement withncontact point |20, then through arms I8 `and ||4 to the center terminaloffthe battery 28., and: then `from 'the .battery 28 through arm r| I2, platemember 46, conductcr32 andsarm 38 to the center terminal of battery l21. lThe opposite end of battery 2.1 is connected 'byarm58 to the light socket 24 which is'iniengagement with the threaded portion of the `bulb 20,whilefthc center terminal |04 thereof i isuin @contact with arm 86 thus completing thecircuit.. However, when it is convenient .for the physician .to employ an external source of energy, andthereby save'the batteries `of vthe instrument^the socket member |62 will be pressed into the terminal block 88 and into engagement with the .terminal members 18 and 83. As the socketis'pressedtinwardly the member |56 is depressed and the contact points |20 and |54 are fopened, so that if the instrument is no-w employed, pressingiof'the push button |00 will establish a circuit which .maymbe traced from the terminal member `18 through conductor 14, plate 54 and socket24 to thebulb. When the -push button .|00 is `pressed and vthe central contactl |04 of the bulb is in engagement with the arm 96 current will pass througharmfrSG, conductor 88 and arm 86 to the terminal member 83,

While the preferred constructionl shown .by Figs. l, 2, 3 and 4 is provided with the socketmember |62 which may-be easily removed from Aengagement with the device by gripping the outer portion |10 thereon, it will be seen in Fig. '7 that the structure may be modied slightly. to arrange the device to function with a ilexible electrical conductor which is not removable from the device but at all times attached thereto. In Fig. 7 'the modied structure comprises a terminal means or junction box |12 which maybe inserted into the end wall of the casing section 2 and secured by suitable means such as a pair of laterally spaced screws |13 extending vertically Ythrough .the block and into lugs in the section 2. This boxv maybe formed by two molded sections |14 and |16 divided longitudinally thereof as at |11 so that a'movable molded two-part socket member I18attacl'1ed1to a iiexibie electric cord .|8| may bepositioned within the box and arranged to move from an Iinoperative outer position shown by Fig. 7, at which time the external source of energy is disconnected from terminals |80, to a left hand or inner position in engagement with the terminals. These terminals correspond to previously described terminal members 18, 83 of Fig. 1 and the movement of said socket member |18 to the left `hand position is such that a rod or tubular member |82 open thefcontact points 420 and 54 in the ymanner previously described. A recess |84 of smaller height than the cam surface |83 is provided in the socket for the rod |82 so that the socket |18 will be yieldably retained in its inner position while the external source of energy is being used. Likewise the cam surface |83 tends to urge the socket |18 toward its outer position after the nger or rim portion |88 thereof has been grasped to move the socket member toward said position. Obviously, in this modied construction the flexible cord |8| and a conventional plug carried thereon may be folded into a compact form or wrapped around the instrument so as to occupy but little space when the device is not in use.

Thus it will be seen that the device of this invention is constructed and arranged to provide a convenient and compact portable instrument for easily measuring the hemoglobin ycontent of the blood, which device facilitates the examination of blood by the physician whether near a source of external current or at locations removed therefrom.

From the foregoing description it will be seen that a simple, compact, eicient and economical means has been provided for obtaining all of the objects of the invention as set forth above.

Having described the invention, I claim:

1. In a portable device of the character described having an elongated casing of such limited size and transverse sectional shape that diametrically opposed exterior surfaces thereof may be conveniently gripped and supported by one hand of an operator, comparison elements within said casing, sighting means in an end wall of said casing and reflecting means in optical alignment therewith and so positioned that said comparison elements may be observed by an operator sighting through said sighting means, a bulb within said casing for projecting light upon said comparison elements, and a longitudinally disposed battery in said casing for energizing said bulb, the combination of terminal means adjacent the end wall of said casing remote from said sighting means for receiving current from an external source, means for operatively connecting said battery means and said terminal means with said bulb, said connecting means comprising a compactly related elongated set of conductors secured to said casing adjacent a side of said battery and having flexible arms extending from an end thereof to form a switch, and a movable member associated with said terminal means for actuating said switch for interrupting the ilow of current from said battery to said bulb when an electrical attachment is brought into operative relationship with said movable member and before it is in operative engagement with said terminal means for supplying said bulb with current from said external source.

2. In a portable hemoglobinometer of the character described comprising an elongated casing of such limited size and transverse sectional shape that diametrically opposed exterior surfaces thereof may be conveniently gripped and supported by one hand of an operator and said casing having readily separable sections, sighting means in an end wall of one of said sections, reflecting means, a specimen holder and a standard cornparison member arranged within one of said sections, said comparison member being' slideable by the other hand of said operator relative to said holder for selectively positioning various portions thereof adjacent said holder during visual comparison therewith, a light bulb within another of said sections and adjacent said holder and comparison member for illuminating same, and

. a pair of batteries longitudinally arranged at op'- posite sides of said light bulb in said second section for energizing said bulb, the combination of terminal means carried adjacent the end wall of said second section remote from said sighting means and having a stationary part and a movable part for receiving electrical energy from an external source, means for connecting said batteries and said terminal means with said bulb, said connecting means comprising a nested set of conductors having a central supporting portion secured to said second section adjacent a side of one of said batteries and having flexible arms extending in opposite directions therefrom, said arms being arranged to form a manually operable switch for controlling the ow of current from said terminal means or said batteries to said bulb and arranged to form a second switch, said second switch being responsive to movement of said movable part to a first position for allowing a flow of current from saidterminal means to said bulb and responsive to movement of said movable part to a second position for allowing a ilow of current from said batteries to said bulb.

3. In a portable device of the character del scribed comprising an elongated casing of such limited size and transverse sectional shape that diametrcally opposed exterior surfaces thereof may be conveniently gripped and supported by one hand of an operator and. said casing having readily separable sections, sighting means in an end wall of one of said sections, reflecting means, a specimen holder and a standard comparison member arranged within said one section, said comparison member being slidable relative to said' holder by the other hand of said operator for selectively positioning various portions thereof adjacent said holder during visual comparison therewith, a light bulb within a second of said sections and adjacent said holder and comparison member for illuminating same, and a pair of batteries longitudinally arranged at opposite sides oi said light bulb in said second section for energizing said bulb, the combination of terminal means carried adjacent the end wall of said second sectionv remote from said sighting means and having a stationary part and a movable part for receiving electrical energy from an external source, means for releasably receiving and retaining said batteries in an operative position and for connecting said batteries and said terminal means to said bulb, said retaining and connecting means comprising a first conductor having a resilient arm engaging a terminal of one of said batteriesv and also comprising a nested set of conductors, having a second resilient arm engaging a terminal of th'e other of said batteries, said nested set of conductors having a central relatively ilat elonteries to said bulb, said pair of flexible arms being arranged to form a second switch responsive to movement of said movable part to a rst position* for allowing a flow of current from said external source through said terminal means to said bulb and responsive to movement of said movable part to a second position for allowing a ilow of current from said batteries to said bulb.

4. In a portable device of the Ycharacter described;comprising an elongated casing of such' limited sizes. andtransverse;sectional shape that diametrically opposedexteriorf. surfaces: thereof mayk be f conveniently grippedtand :supported by one hand of :an operator` and. said'. .casingzhaving readily separable sections, sighting means in an end wall of one of said sections, reflecting means, a specimen holder and a standard comparison member arranged within saidl one section, said comparison member being slideable relative to said holder by the other hand of said operator for selectively positioning various portions thereof adjacent said holder during visual comparison therewith, a light bulb within a second of said sections and adjacent said holder and comparison member for illuminating same, and a pair of batteries longitudinally arranged at opposite sides of said light bulb in said second section for energizing said bulb, the combination of terminal means carried adjacent the end wall of said second section remote from said sighting means and having a stationary part within said second section and a movable part for receiving electrical energy from an external source, said movable part being readily detachable from said device and having a cam surface, means for releasably receiving and retaining said batteries in an operative position and for connecting said batteries and said terminal means to said bulb, said retaining and connecting means comprising a rst conductor having a resilient arm engaging a terminal of one of said batteries and also comprising a nested set of conductors having a second resilient arm engaging a'terminal of the other of said batteries, said nested set of conductors having a central relatively iiat elongated supporting portion secured to said second section adjacent one of said batteries, and also having a pair of flexible arms extending in one direction therefrom and a single flexible arm extending in the opposite direction therefrom, said single arm being arranged to form a manually operable switch for controlling the ow of current from said terminal means or said batteries to said bulb, said pair of exible arms being arranged to form a second switch responsive to movement of said cam surface and movable part to a predetermined operative position within said second section for allowing a ow of current from said external source through said terminal means to said bulb, and responsive to movement of same away from said predetermined position for interrupting said flow from said external source and allowing a ow oi current from said batteries to said bulb.

5. In a portable device of the character described comprising an elongated casing of such limited size and transverse sectional shape that diametrically opposed exterior surfaces thereof may be conveniently gripped and supported by one hand of an operator and said casing having readily separable sections, sighting means in an end wall of one of said sections, reflecting means, a specimen holder and a standard comparison member arranged within said one section, said comparison member being slideable relative to said holder by the other hand of said operator for selectively positioning various portions thereof adjacent said holder during visual comparison therewith, a light bulb within a second of said sections and adjacent said holder and comparison member for illuminating same, and a pair of batteries longitudinally arranged at opposite sides of said light bulb in said second section for energizing said bulb, the combination of terminal source, means for releasably receiving and retaining said batteries in an operative position and for connecting said batteries and said terminal means to said bulb, said retaining andconnectingmeans comprising a irst conductor having a resilient arm engaging a terminal of one of said batteries and also comprising a nested set of conductors having a second resilient arm engaging a terminal of the other of said batteries, said nested set of conductors having a central relatively flat elongated supporting portion secured to said second section adjacent one of said batteries, and also having a pair of exible arms extending in one direction therefrom and a single flexible arm extending in the opposite directiony therefrom, said single arm being arranged to form a manually operable switch for controlling the now of current from said terminal means or said batteries to said bulb, said pair of exible arms being arranged to form a second switch responsive to movement of said movable part to a first position for allowing a iiow of current from said external source through said terminal means to said bulb, and responsive to movement of said movable part to a second position for allowing a ow of current from said batteries to said bulb, and means on said device for retaining said movable part in an operative relation -to said stationary part when moved to either of said positions.

6. In a portable device of the character described having an elongated casing, sighting means in an end wall of said casing, comparison elements in said casing, said casing being of such limited size and transverse sectional shape that diametrically opposed exterior surfaces thereof may be conveniently gripped and supported by one hand of an operator while his other hand is free for adjusting control means for said elements projecting outwardly through said casing, the combination of a light bulb within said casing, a pair of batteries longitudinally arranged at opposite sides of said light bulb for energizing said bulb, terminal means carried adjacent the opposite end wall of said casing and having a stationary part and a movable part for receiving electrical energy from an external source, means for releasably receiving and retaining said batteries in an operative position and for connecting said batteries and said terminal means to said bulb, said retaining and connecting means comprising f a rst conductor having a resilient arm engaging a terminal of one of said batteries and also comprising a nested set of conductors having a second resilient arm engaging a terminal of the other of said batteries, said nested set of conductors comprising a central relatively flat elongated supporting portion secured to said casing adjacent a side of a battery, and also having a pair of ilexible arms extending in one direction therefrom and a single exible arm extending in the opposite direction therefrom, said single arm forming a manually operable switch for controlling the flow of current from said terminal means or said batteries to said bulb, said pair of exible arms being arranged to form a second switch automatically responsive to movement of said movable part toward a iirst position to disconnect said batteries from said manual switch and thereafter establish a connection between said external source and said manual switch, said pair o'f iiexible arms also being effective upon movement of the endwall of s'aidlsecsaid movable terminal part to a second position for allowing a flow of current from said batteries to said switch.

HARRY F. LUNDBERG.

REFERENCES CITED The following references are of record in the le of this patent:

Number 12 UNITED STATES PATENTS Name Date Buttolph June 17, 1930 Zavattaro May 18, 1943 Striker June 19, 1945 Gradisar et al Mar. 12, 1946 

